1. Field of Invention
This invention relates to an adhesive applicator with a new and improved applicator tip design.
2. Description of Related Art
Monomer and polymer adhesives are used in both industrial (including household) and medical applications. Included among these adhesives are the 1,1-disubstituted ethylene monomers and polymers, such as the xcex1-cyanoacrylates. Since the discovery of the adhesive properties of such monomers and polymers, they have found wide use due to the speed with which they cure, the strength of the resulting bond formed, and their relative ease of use. These characteristics have made the xcex1-cyanoacrylate adhesives the primary choice for numerous applications such as bonding plastics, rubbers, glass, metals, wood, and, more recently, biological tissues.
It is known that monomeric forms of xcex1-cyanoacrylates are extremely reactive, polymerizing rapidly in the presence of even minute amounts of an initiator, including moisture present in the air or on moist surfaces such as animal (including human) tissue. Monomers of xcex1-cyanoacrylates are anionically polymerizable or free radical polymerizable, or polymerizable by zwitterions or ion pairs to form polymers. Once polymerization has been initiated, the cure rate can be very rapid.
Medical applications of adhesive compositions include use as an alternate-or an adjunct to surgical sutures and staples in wound closure as well as for covering and protecting surface wounds such as lacerations, abrasions, burns, ulcers such as stomatitis, sores, and other open surface wounds. When such an adhesive is applied, it is usually applied in its monomeric form, and the resultant polymerization gives rise to the desired adhesive bond.
However, with the application of adhesive in a monomeric form, due to the rapid polymerization rate of the monomers, it has been challenging to design effective and commercially viable packaging and dispensing systems. Such packaging and dispensing systems must counterbalance the competing requirements that the monomer not prematurely polymerize, that the monomer be easily applied, that the monomer polymerize at a desired rate upon application, and that the sanitary and/or sterile properties of the monomer and applicatorxe2x80x94whether real or perceivedxe2x80x94be maintained.
Various dispensing and packaging systems for adhesives have been proposed. These systems include large bottles with a single applicator, such as a large single- or multi-use brush; small applicators such as small ampoules containing monomer that can be expelled through an integral or replaceable applicator; and the like.
A disadvantage of some known applicator systems, and particularly applicators containing a frangible vial and a porous applicator tip for expelling the adhesive, is that the monomer material is expelled through the entire surface area of the tip, and even to greater extents in areas other than the area used to apply the monomer to the desired substrate. For example, large amounts of adhesive are expelled from areas around the periphery of the applicator tip, where the applicator tip meets the applicator housing, rather than through the end of the applicator tip, as is often desired. This leads to a further problem of less precise control over the area of application of the monomer to the substrate.
For example, an effective applicator system is disclosed in U.S. Pat. No. 5,928,611 to Leung. This patent discloses an applicator system generally comprising a tube containing a frangible vial of monomeric adhesive composition. One end of the tube is sealed, and the other end is closed by an applicator tip comprising a solid support having a polymerization or cross-linking accelerator or initiator for the monomeric adhesive disposed thereon or therein. As shown in FIG. 3 of the patent, the applicator tip can be generally dome shaped. The applicator device of U.S. Pat. No. 5,928,611 is shown as FIG. 1 herein. An applicator device 100 comprises a cylindrical applicator container 200 holding polymerizable and/or cross-linkable material 300 enclosed in a frangible vial 400, and an applicator tip 500 containing a polymerization and/or cross-linking initiator.
However, a difficulty encountered with such a dome-shaped applicator tip, as well as with other solid applicator tips, is that the monomeric adhesive material being expelled through the applicator tip tends to follow paths of least resistance within the tip. That is, as the monomeric adhesive is being expelled, it tends to follow the shortest paths through the tip, which tend to be around the periphery of the tip, rather than following the longer path through the full length of the tip to the end of the tip. Because the end of the tip is desired to be used to apply the adhesive, less precise control of placement of the adhesive is obtained because adhesive is expelled through the entire surface of the tip. This also tends to result in waste of adhesive material, because all of the adhesive does not exit from the tip at the desired location.
A related problem with such applicator tips is that it is difficult to obtain precise placement of the adhesive materials in some uses. For example, it is often difficult to precisely apply the adhesive material in confined spaces, where it is difficult to fit the entire applicator device. Likewise, it is difficult to apply fine lines of the adhesive from such a dome-shaped applicator tip. In such medical procedures as face lifts or intricate surgery, for example, high precision is necessary.
Applicator devices used for Loctite Product No. 11067-2 and Permatex Product No. ATA-1 contain crushable glass ampoules within flexible applicators. However, the compositions within the crushable ampoules are, in both products, adhesive activators, not the adhesive composition itself. In both of these products, the adhesive is contained in a separate dispenser. The dispenser system used for these products is physically similar to that shown in FIG. 1, except that the applicator tip is rectangular in shape, rather than dome-shaped, and the applicator tip does not contain a polymerization and/or cross-linking initiator for an adhesive material contained in the frangible vial. In this product also, the above-described problems of wasted material (here, activator) and less precision in application are also present.
EP 0 170 526 discloses an applicator device for storing and dispensing a two-component product, such as a two-component adhesive. The applicator includes an inner sealed frangible ampoule containing a curable material, an outer flexible sleeve containing the ampoule, with a dispensing nozzle at one end and being sealed at the other end, and a fibrous material impregnated with accelerant. The fibrous material is positioned at least partly around the ampoule at the orifice end of the container between the ampoule and a nozzle.
Accordingly, a need exists in the art for adhesive applicators that will allow more precise placement of the adhesive material. A need also exists in the art for a means to decrease waste of monomeric adhesive material. Still further, a need exists in the art for different types of applicator tip designs, to allow a broader range of use of the adhesive materials.
The present invention addresses the above and other needs by providing applicator tips that allow increased precision in control of placement of the adhesive composition, and a decrease in waste of adhesive. Applicator tips of embodiments of the present invention can direct the adhesive material that is being expelled from the applicator to a specific desired point, while maintaining control over the flow of the adhesive material.
A benefit provided by the present invention is thus the ability to apply adhesive material in precise patterns, such as in thin lines, which was either more difficult or not possible using prior applicator systems. The present invention also allows tailoring of the application pattern based on alternative designs of the applicator tip, thus allowing flexibility in application of, for example, from thin lines to thicker lines. The present invention also permits decreased waste of adhesive material, by allowing effective use of a greater portion of the volume of adhesive material contained within the applicator.
In embodiments, the present invention provides an applicator for dispensing adhesive material, comprising:
a container body, and
an applicator tip, wherein said adhesive material is located in said container body in a non-contacting relationship with said applicator tip prior to dispensing said adhesive material,
said applicator tip having a proximal open end open toward said container body for attachment to said container body, a distal end having at least one orifice, a restrictive flow portion located between said proximal end and said distal end, and a flow reducing portion located between said restrictive flow portion and said distal end,
said applicator tip defining a fluid flow channel from said proximal end to said distal end and through said restrictive flow portion and said flow reducing portion,
wherein said applicator tip permits said adhesive material to pass through said applicator tip and exit said applicator tip at said at least one orifice.
In embodiments, the present invention provides a kit for dispensing adhesive material, comprising at least one saleable package containing: at least one applicator comprising a container body and an adhesive material located in the container body, and at least two applicator tips that are attachable to the applicator and have different configurations, wherein said kit contains more applicator tips than applicators.